1. Technical Field
This application generally relates to a medical device, and more particularly, to a surgical access device comprising a seal comprising an instrument contact element extending through a compression element.
2. Description of the Related Art
Minimally invasive surgery is a type of surgery in which instruments access the interior of a patient's body through one or more surgical access devices traversing a body wall. Laparoscopic surgery is a type of minimally invasive surgery. Surgical access devices used in minimally invasive surgery include trocars or cannulas, single ports, and hand ports. Instruments access the interior of the patient's body through an instrument access channel in the access device, which includes a valve or seal that forms a seal with the instrument.
In some cases, a surgical procedure is performed in a body cavity inflated or insufflated with an insufflation gas, for example, carbon dioxide, which lifts an overlying body wall away from an organ bed within the body cavity, thereby providing a surgeon with a less obstructed surgical field. Where the body cavity is the abdomen, the insufflated condition is referred to as “pneumoperitoneum”. Surgical access devices used under pneumoperitoneum seal the access channel both in the presence and the absence of instruments extending therethrough, thereby preventing loss of pneumoperitoneum.
A typical trocar seal includes an elastic septum seal and a shield that protects the septum seal from damage, for example, tears and/or punctures, from contact with instruments. Typical septum shields and/or protectors, however, do not protect the orifice of the septum from damage. An exposed portion of the septum seal around the orifice directly contacts and seals against the instrument. Exposing the edge of the septum around the orifice to an instrument exposes a vulnerable portion of the seal to aggressive surface features found on some instruments. The exposed portion of the septum seal around the orifice is placed under immense stress while an instrument is inserted through the trocar, making the material around the orifice susceptible to nicks or cuts caused by contact with surgical instruments, particularly instruments that include sharp edges, undercuts, protuberances, and/or other challenging geometries.
Numerous technical challenges confront those designing and manufacturing septum seals, for example, handling irregularly shaped surgical instruments, and balancing durability with drag force or friction between the seal and surgical instruments. Elastomeric seal materials elongate when instruments are inserted, thereby increasing drag force. For example, a thick septum is resilient and durable, but exhibits a high instrument drag force from overcoming the restoring force generated by expanding a small diameter orifice with a large diameter instrument. Oil canning, or inversion, of typical septum seals can also result in loss of precise instrument movement because the surgeon experiences a different feedback or feel between large and small changes in the position of the instrument. An hour-glass-shaped septum seal can be stretched during instrument insertion, which also increases the drag force.